First report of Halomicrobium mukohataei in Mexico and its biological activity

Haloarchaea produce metabolites of biotechnological importance and grow in hypersaline environments such as coastal lagoons, marine solar, salterns, natural brines, and salt lakes. Haloarchaeal compounds from hypersaline environments in Mexico have been scarcely studied. This research aimed to identify a haloarchaea isolate and evaluate the antioxidant, antimicrobial, and cytotoxic properties of the culture's biomass pigments (BP) and supernatant pigments (SP). One extremely halophilic archaeal strain designated AS8, isolated brine from the coastal lagoon of "Bahía de Lobos," Sonora was identified as Halomicrobium mukohataei based on analyses del gen 16S rRNA were related closely to with 100% similarity. The supernatant pigments (SP) showed the best free radical scavenging activity on DPPH and ABTS assays, with 75 and 68% inhibition values, respectively. The extracts also showed significant antibacterial activity against Gram-positive and Gram-negative bacteria with inhibition halos between 7 to 17 mm. Cytotoxic activity of extracts using nauplii of Artemia salina showed CL ₅₀ 850 µg/mL to SP and >1000 µg/mL to BP. Phylogenetic analysis showed that the strain belongs to the genus Halomicrobium mukohataei . This work represents the first study of isolating H. mukohataei from the coastal lagoon "Bahía de Lobos." Also, the potential biological activity of its pigments suggests potential biomedical applications as an alternative source of natural pigments with antioxidant, antimicrobial, and cytotoxic properties.